Have you checked eBay? There are often sellers with sets of cams for different machines. They usually specify which machine they are for.
The user's manual for the machine probably lists the cams and which ones to use to produce which stitches. Maybe someone with a user's manual for a machine that uses cams can verify that.
Cams were the old way to make a machine produce fancy stitches -- a mechanical way to do it. Now it is all done electronically.